Md. Code, Tax - General § 12–202

(a) A wholesaler shall complete and file with the Comptroller a tobacco tax return:

(1) for cigarettes:

(i) on or before the 21st day of the month that follows the month in which the wholesaler has the first possession, in the State, of unstamped cigarettes for which tax stamps are required; and

(ii) if the Comptroller so specifies, by regulation, on other dates for each month in which the wholesaler does not have the first possession of any unstamped cigarettes in the State; and

(2) for other tobacco products, on or before the 21st day of the month that follows the month in which the wholesaler has possession of other tobacco products on which the tobacco tax has not been paid.

(b) Each return shall state the quantity of cigarettes or the wholesale price of other tobacco products sold during the period that the return covers.